The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Today, positioning devices, such as Global Positioning Service (GPS) receivers, are widely used to determine a geographic location of a person or an object. For example, a camera equipped with a GPS receiver determines the position of the camera in the GPS coordinate system at the time a photograph is taken and stores the determined GPS coordinates with the photograph as positioning data, which later can be used to determine what is depicted in the photograph (e.g., which building in what city), for example. Further, a GPS receiver may be installed in a vehicle for use in navigation or tracking the vehicle.
However, in some situations, positioning data fails to indicate the geographic location with the desired precision. For example, GPS generally has a margin of error of approximately 15 meters. In so-called “urban canyons,” or city locations at which tall buildings obscure or reflect GPS signals, the problem of imprecise coordinates is particularly prevalent.